Radiometric dating of the Ootun palaeosol and its implication for the age of the Shifting Sand in Ngorongoro Lengai Geopark (Arusha, Tanzania)

• Autorzy: Makongoro Mohamed Zengo , Vegi Maheswara Rao , Vuai Said Ali Hamad , Msabi Michael Mwita

Identyfikatory

DOI

10.14746/logos.2022.28.3.0003

• Języki publikacji: EN

Abstrakty

EN

The Shifting Sand is a barchan dune in Ngorongoro Lengai Geopark in Arusha, Tanzania. The geopark, a UNESCO World Heritage Site, is protected by the Ngorongoro Conservation Area Authority. The dune ranks amongst the main geosites that have been attracting numerous tourists; it formed as a result of volcanic ash eruptions that led to tephra deposition on a palaeosol (palaeosurface) in the Ootun area. The easterly winds modified the ash into dunes and headed to the Olduvai Gorge area. The age of the Shifting Sand dune is not known in detail. In the present study, we employ the radiocarbon (14C) dating method to date a subsurface palaeosol bed in the Ootun area where the tephra (i.e., original Shifting Sand materials) was originally deposited. An Accelerator Mass Spectrometer was used to determine the carbon-14 date of the palaeosol so as to estimate the age of the Shifting Sand dune, and an Energy Dispersive X-ray Fluorescent Spectrometer to determine the chemical composition of the Shifting Sand material and the tephra bed for correlative purposes. A radiocarbon (14C) date of 2510 ± 30 years BP for the Ootun palaeosol was obtained to estimate the minimum age of the Ootun subsurface tephra deposited in the area; since then, this started to move westwards towards the Olduvai Gorge area, where it is today defined as the Shifting Sand. The current findings add educational value to the Shifting Sand in Ngorongoro Lengai Geopark and improve our understanding of the eruption history of the Gregory Rift volcanoes.

Słowa kluczowe

EN

Oldoinyo Lengai volcano; ash dunes; tephra dunes; carbon-14 dating; UNESCO Global Geopark

PL

wulkan Oldoinyo Lengai; wydmy; datowanie radiowęglowe; Światowy Geopark UNESCO; Tanzania

• Wydawca: Uniwersytet im. Adama Mickiewicza. Instytut Geologii
• Czasopismo: Geologos
• Rocznik: 2022
• Tom: Vol. 28, No. 3
• Strony: 203--215
• Opis fizyczny: Bibliogr. 34 poz.

Twórcy

autor

Makongoro Mohamed Zengo

• Laboratory Directorate, Geological Survey of Tanzania, P.O. Box 903, Dodoma, Tanzania
• Department of Chemistry, College of Natural and Mathematical Sciences, The University of Dodoma, P.O. Box 259, Dodoma, Tanzania

autor

Vegi Maheswara Rao

• Department of Chemistry, College of Natural and Mathematical Sciences, The University of Dodoma, P.O. Box 259, Dodoma, Tanzania

autor

Vuai Said Ali Hamad

• Department of Chemistry, College of Natural and Mathematical Sciences, The University of Dodoma, P.O. Box 259, Dodoma, Tanzania

autor

Msabi Michael Mwita

• Department of Geology, College of Earth Sciences and Engineering, The University of Dodoma, P.O. Box 259, Dodoma, Tanzania

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Uwagi

Opracowanie rekordu ze środków MNiSW, umowa nr SONP/SP/546092/2022 w ramach programu "Społeczna odpowiedzialność nauki" - moduł: Popularyzacja nauki i promocja sportu (2024).